<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        var flag = true;
        if(flag){
            //条件为true 执行这里的代码
            //条件为false 不执行这里的代码
            console.log("条件为true");
        }



    </script>
</body>
</html>